Recent development of substrates for immobilization of bimetallic nanoparticles for wastewater treatment: a review.

Bimetallic nanoparticles (BMNPs) have gained considerable attention due to their remarkable catalytic properties, making them invaluable in wastewater treatment applications. One of these challenges lies in the propensity of BMNPs to aggregate due to Van der Waals interactions, which can reduce their overall performance. Additionally, retrieving exhausted NPs from the treated solution for subsequent reuse remains a significant hurdle. Moreover, the leaching of NPs into the discharged wastewater can have harmful effects on humans as well as aquatic life. To overcome these issues, various substrates have been researched to maximize the efficiency and stability of the NPs. This review paper delves into the pivotal role of various substrates in immobilizing BMNPs, providing a comprehensive analysis of their performances, advantages, and drawbacks. The substrates encompass a diverse range of materials, including organic, inorganic, organic-inorganic, beads, fibers, and membranes. Each substrate type offers unique attributes, influencing the stability, efficiency, and recyclability of BMNPs. This review paper aims to provide an up-to-date and detailed analysis and comparison of the substrates used for the immobilization of BMNPs. This work further reviews the underlying mechanisms of the composites involved in treating pollutants from wastewater and how these mechanisms are enhanced by the synergistic effects produced by the substrate and BMNPs. Furthermore, the reusability and sustainability of these composites are discussed. Also, high-performing substrates are highlighted to give direction to future research focusing on the immobilization of BMNPs in the application of wastewater treatment.

Water pathways through the ages: Integrated laundry wastewater treatment for pollution prevention.

Rapid urbanization and the rising global population have led to the generation of substantial volumes of laundry wastewater. Accordingly, treatment of laundry wastewater has been advocated to curb water pollution and achieve water sustainability. However, technological limitations in treating (specifically) laundry wastewater and the lack of regulations governing the levels of contaminants for such discharges have been perennial problems. This review bridges the knowledge gap by delineating the feasibility of current technologies in laundry wastewater treatment and the experiences of various countries in adopting different approaches. Besides, the feasible methods for collecting laundry wastewater are elaborated. The development of the treatment technologies is highlighted, in which the integrated-treatment processes (physicochemical, biological, and combination of both) are critically discussed based on their functions and methods. A judicious selection of the technologies not only improves the energy efficiency and quality of the treated wastewater, but also mitigates capitals and operational costs. This is projected to enhance public acceptance towards the reuse of laundry wastewater. Thus, the comprehensive assessment herein is envisioned to insightfully guide national policymakers in exploring the viability of the technologies and water-recycling projects. Future research should focus on the techno-economic aspects of the treatment processes, especially their industrial scale-up.